Nearly 15 percent of new ride-hail drivers in Maryland have been booted from the apps over the past six months for failing state screening, despite having passed Uber and Lyft's background checks, according to the state Public Service Commission (PSC).

In more than 95 percent of cases, the rejected applicants had been driving for Uber, the commission said.

The rejections included 460 applicants with disqualifying criminal histories and 900 who were flagged because of issues with their driving records, according to the PSC.

Uber blamed "outdated" screening requirements for the outsize number of rejections and said fewer drivers would be blocked as new screening criteria were rolled out by the state. The company said it followed a legal standard established by the commission in December 2015, but PSC staff had been applying broader vetting criteria until last week.

The commission hailed the rejections as evidence that its multitiered screening process is working to weed out bad-apple drivers.

For some, however, the numbers renew concerns about the effectiveness of Uber and Lyft's electronic screening, particularly as other states weigh adopting Maryland's screening model.

The Maryland PSC approved a new screening framework last year after commissioners agreed electronic checks — paired with rigorous oversight by regulators — could be as or more thorough than fingerprint-based checks favored by law enforcement.

But the uptick in rejections, six months after Maryland reported that it had booted more than 4,000 out of 74,000 drivers since December 2015, shows a significant gap between ride-hail companies' screening and state regulators' expectations. In the latest round of checks, Maryland rejected 3,503 out of 24,608 applications evaluated since April 3. Over the six-month span, the proportion of rejections nearly tripled compared with the year-and-a-half before.

Maryland does not conduct its own separate screenings of drivers but rather reviews Uber's and Lyft's completed applications for compliance. Once Uber and Lyft approve individuals to drive, they can pick up fares until the state says otherwise.

Virginia and the District do not collect the companies' screening data to check for compliance.

"The fact that we are rejecting a significant number on secondary review demonstrates a solid justification for our supplemental review process, which is above and beyond what most other states do," PSC spokeswoman Tori Leonard said.

In addition to the 24,608 applications already checked, another 6,922 applications received since April 3 have yet to be reviewed. Since December 2015, the state has rejected about 6.6 percent of the applications it has received, Leonard said.

In the latest batch, nearly 40 percent of the rejected drivers were dismissed for driving or criminal history reasons, according to stats provided by Leonard. The remaining drivers were rejected for administrative reasons, which could include the failure to verify a driver's identity, having too little driving experience, and holding a limited-term temporary license.

Uber defended its screening process and argued that state regulators were evaluating its drivers based upon an obsolete standard.

"There is a consensus among the Public Service Commissioners, PSC staff, and ridesharing companies on the responsible, fair, and clear standards for screenings," an Uber spokesman said in a statement. "These standards are in line with the PSC's ruling on screening requirements last year, they are similar to the laws in neighboring D.C. and Virginia, and they are expected to be finalized within the next few months. Unfortunately, despite this consensus, some ride-share driver applicants are being blocked under an outdated criteria while the new rules are being finalized."

Last year, as concerns arose over the effectiveness of ride-hail companies' electronic screening, the PSC debated whether to institute fingerprint-based background checks. Uber threatened to leave the state if it adopted the checks, largely because of the limitations the costly screenings would place on its workforce. In the end, the commission approved an alternative screening method that allowed the companies to continue conducting electronic checks — subject to final approval by the state.

Uber also had opposed provisions that, for example, banned drivers who were convicted of a single felony drug possession charge, according to the company. But a new rule approved by the commission would reinstate drivers' eligibility after seven years, or after 10 years for multiple convictions.

The new PSC screening requirements, which went into effect last week, are more in line with Uber's approach to screening, the company said.

Lyft did not respond directly to questions about the discrepancy between its checks and the state's secondary screening but said the majority of rejections are for what it described as "paperwork issues," which could include submitting photos of vehicle inspection stickers rather than the actual certificates.

One positive note for the ride-hail companies: Between April and October, the proportion of drivers rejected for driving and criminal history reasons decreased. In statistics released in April, the number of drivers rejected for driving and criminal history was 64 percent; the number rejected for those reasons between April and October dropped to 39 percent.

"As our screening guidelines continue to evolve as a result of new regulations and practices, we believe this will lead to more stability and even a decrease in the number of safety-related rejections going forward," Leonard said.

Still, Dave Sutton, a spokesman for the taxi industry-funded Who's Driving You, said the findings are alarming.

"This is further proof that governments should be conducting background checks on Uber and Lyft drivers, not the companies themselves," he said. "While Uber points to Maryland as a proponent of its background checks, the state is quietly rejecting thousands of already approved applicants. This should serve as a warning to other states and cities."

Meanwhile, in California, the state Public Utilities Commission recently reached a "proposed decision" that would not subject drivers to fingerprint checks. The decision notes that Maryland regulators found Uber's and Lyft's screenings to be "as comprehensive and accurate" as fingerprint-based checks.

"In California, the state regulator has decided not to fingerprint Uber and Lyft drivers based on Uber's testimony that Maryland approves of the company's driver screening," said Sutton, whose organization raises concerns about the companies' screening processes. "Clearly, Maryland does not."